In a new paper about exercise and the impact on the heart, cardiologist Professor Sanjay Sharma says: "The benefits of exercise are irrefutable. Individuals engaging in regular exercise have a favourable cardiovascular risk profile for coronary artery disease and reduce their risk of myocardial infarction (heart attacks) by 50%."

But in a word of warning he also writes: "Intense exercise may infrequently trigger arrhythmogenic sudden cardiac death in an athlete harbouring asymptomatic cardiac disease."

The paper states: “Exercise promotes longevity of life, reduces the risk of some malignancies, retards the onset of dementia, and is as considered an antidepressant. Most of these benefits are attributable to moderate exercise, whereas athletes perform way beyond the recommended levels of physical activity and constantly push back the frontiers of human endurance.

“The cardiovascular adaptation for generating a large and sustained increase in cardiac output during prolonged exercise includes a 10–20% increase in cardiac dimensions. In rare instances, these physiological increases in cardiac size overlap with morphologically mild expressions of the primary cardiomyopathies and resolving the diagnostic dilemma can be challenging.